Intraocular lenses have been heretofore successfully implanted in human eyes. For example, anterior chamber lenses have been implanted directly behind the cornea, but such a lens is sometimes considered undesirable in that it is positioned very close to the cornea and in some cases may result in traumatization of the endothelium. In order to minimize the problems of anterior chamber lenses, various iris-clip and iridocapsular lenses have been developed.
There have been many other designs of intraocular lenses and the latest and most popular intraocular lens involves the use of posterior chamber lenses. The reason for the popularity of the posterior chamber lens is predominantly because many that are skilled in the art believe that breaking or incising the posterior capsule of the lens results in a higher incidence of retinal detachment and cystoid macula edema. These complications appear to be decreased in any type of extracapsular cataract extraction whether it is done in the standard manner or by the procedures of lensectomy or phacoemulsification.
However, one of the present problems with intraocular lenses is that it is necessary to decide on the power of the lens preoperatively. This can be accomplished, for example, by performing an ultrasound scan and/or evaluating the patient's refraction preoperatively and then making a clinical estimate of the proper power of the lens in order to determine proper refraction of the eye.
Accordingly, there is a need for a posterior chamber lens having a variable power of refraction.